crypto/api.c

   1 /*
   2  * Scatterlist Cryptographic API.
   3  *
   4  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
   5  * Copyright (c) 2002 David S. Miller (davem@redhat.com)
   6  * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
   7  *
   8  * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
   9  * and Nettle, by Niels Möller.
  10  *
  11  * This program is free software; you can redistribute it and/or modify it
  12  * under the terms of the GNU General Public License as published by the Free
  13  * Software Foundation; either version 2 of the License, or (at your option)
  14  * any later version.
  15  *
  16  */
  17
  18 #include <linux/err.h>
  19 #include <linux/errno.h>
  20 #include <linux/kernel.h>
  21 #include <linux/kmod.h>
  22 #include <linux/module.h>
  23 #include <linux/param.h>
  24 #include <linux/sched.h>
  25 #include <linux/slab.h>
  26 #include <linux/string.h>
  27 #include "internal.h"
  28
  29 LIST_HEAD(crypto_alg_list);
  30 EXPORT_SYMBOL_GPL(crypto_alg_list);
  31 DECLARE_RWSEM(crypto_alg_sem);
  32 EXPORT_SYMBOL_GPL(crypto_alg_sem);
  33
  34 BLOCKING_NOTIFIER_HEAD(crypto_chain);
  35 EXPORT_SYMBOL_GPL(crypto_chain);
  36
  37 struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
  38 {
  39         return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
  40 }
  41 EXPORT_SYMBOL_GPL(crypto_mod_get);
  42
  43 void crypto_mod_put(struct crypto_alg *alg)
  44 {
  45         struct module *module = alg->cra_module;
  46
  47         crypto_alg_put(alg);
  48         module_put(module);
  49 }
  50 EXPORT_SYMBOL_GPL(crypto_mod_put);
  51
  52 static inline int crypto_is_test_larval(struct crypto_larval *larval)
  53 {
  54         return larval->alg.cra_driver_name[0];
  55 }
  56
  57 static struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type,
  58                                               u32 mask)
  59 {
  60         struct crypto_alg *q, *alg = NULL;
  61         int best = -2;
  62
  63         list_for_each_entry(q, &crypto_alg_list, cra_list) {
  64                 int exact, fuzzy;
  65
  66                 if (crypto_is_moribund(q))
  67                         continue;
  68
  69                 if ((q->cra_flags ^ type) & mask)
  70                         continue;
  71
  72                 if (crypto_is_larval(q) &&
  73                     !crypto_is_test_larval((struct crypto_larval *)q) &&
  74                     ((struct crypto_larval *)q)->mask != mask)
  75                         continue;
  76
  77                 exact = !strcmp(q->cra_driver_name, name);
  78                 fuzzy = !strcmp(q->cra_name, name);
  79                 if (!exact && !(fuzzy && q->cra_priority > best))
  80                         continue;
  81
  82                 if (unlikely(!crypto_mod_get(q)))
  83                         continue;
  84
  85                 best = q->cra_priority;
  86                 if (alg)
  87                         crypto_mod_put(alg);
  88                 alg = q;
  89
  90                 if (exact)
  91                         break;
  92         }
  93
  94         return alg;
  95 }
  96
  97 static void crypto_larval_destroy(struct crypto_alg *alg)
  98 {
  99         struct crypto_larval *larval = (void *)alg;
 100
 101         BUG_ON(!crypto_is_larval(alg));
 102         if (larval->adult)
 103                 crypto_mod_put(larval->adult);
 104         kfree(larval);
 105 }
 106
 107 struct crypto_larval *crypto_larval_alloc(const char *name, u32 type, u32 mask)
 108 {
 109         struct crypto_larval *larval;
 110
 111         larval = kzalloc(sizeof(*larval), GFP_KERNEL);
 112         if (!larval)
 113                 return ERR_PTR(-ENOMEM);
 114
 115         larval->mask = mask;
 116         larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;
 117         larval->alg.cra_priority = -1;
 118         larval->alg.cra_destroy = crypto_larval_destroy;
 119
 120         strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
 121         init_completion(&larval->completion);
 122
 123         return larval;
 124 }
 125 EXPORT_SYMBOL_GPL(crypto_larval_alloc);
 126
 127 static struct crypto_alg *crypto_larval_add(const char *name, u32 type,
 128                                             u32 mask)
 129 {
 130         struct crypto_alg *alg;
 131         struct crypto_larval *larval;
 132
 133         larval = crypto_larval_alloc(name, type, mask);
 134         if (IS_ERR(larval))
 135                 return ERR_CAST(larval);
 136
 137         atomic_set(&larval->alg.cra_refcnt, 2);
 138
 139         down_write(&crypto_alg_sem);
 140         alg = __crypto_alg_lookup(name, type, mask);
 141         if (!alg) {
 142                 alg = &larval->alg;
 143                 list_add(&alg->cra_list, &crypto_alg_list);
 144         }
 145         up_write(&crypto_alg_sem);
 146
 147         if (alg != &larval->alg)
 148                 kfree(larval);
 149
 150         return alg;
 151 }
 152
 153 void crypto_larval_kill(struct crypto_alg *alg)
 154 {
 155         struct crypto_larval *larval = (void *)alg;
 156
 157         down_write(&crypto_alg_sem);
 158         list_del(&alg->cra_list);
 159         up_write(&crypto_alg_sem);
 160         complete_all(&larval->completion);
 161         crypto_alg_put(alg);
 162 }
 163 EXPORT_SYMBOL_GPL(crypto_larval_kill);
 164
 165 static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
 166 {
 167         struct crypto_larval *larval = (void *)alg;
 168         long timeout;
 169
 170         timeout = wait_for_completion_interruptible_timeout(
 171                 &larval->completion, 60 * HZ);
 172
 173         alg = larval->adult;
 174         if (timeout < 0)
 175                 alg = ERR_PTR(-EINTR);
 176         else if (!timeout)
 177                 alg = ERR_PTR(-ETIMEDOUT);
 178         else if (!alg)
 179                 alg = ERR_PTR(-ENOENT);
 180         else if (crypto_is_test_larval(larval) &&
 181                  !(alg->cra_flags & CRYPTO_ALG_TESTED))
 182                 alg = ERR_PTR(-EAGAIN);
 183         else if (!crypto_mod_get(alg))
 184                 alg = ERR_PTR(-EAGAIN);
 185         crypto_mod_put(&larval->alg);
 186
 187         return alg;
 188 }
 189
 190 struct crypto_alg *crypto_alg_lookup(const char *name, u32 type, u32 mask)
 191 {
 192         struct crypto_alg *alg;
 193
 194         down_read(&crypto_alg_sem);
 195         alg = __crypto_alg_lookup(name, type, mask);
 196         up_read(&crypto_alg_sem);
 197
 198         return alg;
 199 }
 200 EXPORT_SYMBOL_GPL(crypto_alg_lookup);
 201
 202 struct crypto_alg *crypto_larval_lookup(const char *name, u32 type, u32 mask)
 203 {
 204         struct crypto_alg *alg;
 205
 206         if (!name)
 207                 return ERR_PTR(-ENOENT);
 208
 209         mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
 210         type &= mask;
 211
 212         alg = crypto_alg_lookup(name, type, mask);
 213         if (!alg) {
 214                 request_module("%s", name);
 215
 216                 if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask &
 217                       CRYPTO_ALG_NEED_FALLBACK))
 218                         request_module("%s-all", name);
 219
 220                 alg = crypto_alg_lookup(name, type, mask);
 221         }
 222
 223         if (alg)
 224                 return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;
 225
 226         return crypto_larval_add(name, type, mask);
 227 }
 228 EXPORT_SYMBOL_GPL(crypto_larval_lookup);
 229
 230 int crypto_probing_notify(unsigned long val, void *v)
 231 {
 232         int ok;
 233
 234         ok = blocking_notifier_call_chain(&crypto_chain, val, v);
 235         if (ok == NOTIFY_DONE) {
 236                 request_module("cryptomgr");
 237                 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
 238         }
 239
 240         return ok;
 241 }
 242 EXPORT_SYMBOL_GPL(crypto_probing_notify);
 243
 244 struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
 245 {
 246         struct crypto_alg *alg;
 247         struct crypto_alg *larval;
 248         int ok;
 249
 250         if (!((type | mask) & CRYPTO_ALG_TESTED)) {
 251                 type |= CRYPTO_ALG_TESTED;
 252                 mask |= CRYPTO_ALG_TESTED;
 253         }
 254
 255         larval = crypto_larval_lookup(name, type, mask);
 256         if (IS_ERR(larval) || !crypto_is_larval(larval))
 257                 return larval;
 258
 259         ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
 260
 261         if (ok == NOTIFY_STOP)
 262                 alg = crypto_larval_wait(larval);
 263         else {
 264                 crypto_mod_put(larval);
 265                 alg = ERR_PTR(-ENOENT);
 266         }
 267         crypto_larval_kill(larval);
 268         return alg;
 269 }
 270 EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
 271
 272 static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
 273 {
 274         const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
 275
 276         if (type_obj)
 277                 return type_obj->init(tfm, type, mask);
 278
 279         switch (crypto_tfm_alg_type(tfm)) {
 280         case CRYPTO_ALG_TYPE_CIPHER:
 281                 return crypto_init_cipher_ops(tfm);
 282
 283         case CRYPTO_ALG_TYPE_COMPRESS:
 284                 return crypto_init_compress_ops(tfm);
 285
 286         default:
 287                 break;
 288         }
 289
 290         BUG();
 291         return -EINVAL;
 292 }
 293
 294 static void crypto_exit_ops(struct crypto_tfm *tfm)
 295 {
 296         const struct crypto_type *type = tfm->__crt_alg->cra_type;
 297
 298         if (type) {
 299                 if (tfm->exit)
 300                         tfm->exit(tfm);
 301                 return;
 302         }
 303
 304         switch (crypto_tfm_alg_type(tfm)) {
 305         case CRYPTO_ALG_TYPE_CIPHER:
 306                 crypto_exit_cipher_ops(tfm);
 307                 break;
 308
 309         case CRYPTO_ALG_TYPE_COMPRESS:
 310                 crypto_exit_compress_ops(tfm);
 311                 break;
 312
 313         default:
 314                 BUG();
 315         }
 316 }
 317
 318 static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
 319 {
 320         const struct crypto_type *type_obj = alg->cra_type;
 321         unsigned int len;
 322
 323         len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
 324         if (type_obj)
 325                 return len + type_obj->ctxsize(alg, type, mask);
 326
 327         switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
 328         default:
 329                 BUG();
 330
 331         case CRYPTO_ALG_TYPE_CIPHER:
 332                 len += crypto_cipher_ctxsize(alg);
 333                 break;
 334
 335         case CRYPTO_ALG_TYPE_COMPRESS:
 336                 len += crypto_compress_ctxsize(alg);
 337                 break;
 338         }
 339
 340         return len;
 341 }
 342
 343 void crypto_shoot_alg(struct crypto_alg *alg)
 344 {
 345         down_write(&crypto_alg_sem);
 346         alg->cra_flags |= CRYPTO_ALG_DYING;
 347         up_write(&crypto_alg_sem);
 348 }
 349 EXPORT_SYMBOL_GPL(crypto_shoot_alg);
 350
 351 struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
 352                                       u32 mask)
 353 {
 354         struct crypto_tfm *tfm = NULL;
 355         unsigned int tfm_size;
 356         int err = -ENOMEM;
 357
 358         tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
 359         tfm = kzalloc(tfm_size, GFP_KERNEL);
 360         if (tfm == NULL)
 361                 goto out_err;
 362
 363         tfm->__crt_alg = alg;
 364
 365         err = crypto_init_ops(tfm, type, mask);
 366         if (err)
 367                 goto out_free_tfm;
 368
 369         if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
 370                 goto cra_init_failed;
 371
 372         goto out;
 373
 374 cra_init_failed:
 375         crypto_exit_ops(tfm);
 376 out_free_tfm:
 377         if (err == -EAGAIN)
 378                 crypto_shoot_alg(alg);
 379         kfree(tfm);
 380 out_err:
 381         tfm = ERR_PTR(err);
 382 out:
 383         return tfm;
 384 }
 385 EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
 386
 387 /*
 388  *      crypto_alloc_base - Locate algorithm and allocate transform
 389  *      @alg_name: Name of algorithm
 390  *      @type: Type of algorithm
 391  *      @mask: Mask for type comparison
 392  *
 393  *      This function should not be used by new algorithm types.
 394  *      Plesae use crypto_alloc_tfm instead.
 395  *
 396  *      crypto_alloc_base() will first attempt to locate an already loaded
 397  *      algorithm.  If that fails and the kernel supports dynamically loadable
 398  *      modules, it will then attempt to load a module of the same name or
 399  *      alias.  If that fails it will send a query to any loaded crypto manager
 400  *      to construct an algorithm on the fly.  A refcount is grabbed on the
 401  *      algorithm which is then associated with the new transform.
 402  *
 403  *      The returned transform is of a non-determinate type.  Most people
 404  *      should use one of the more specific allocation functions such as
 405  *      crypto_alloc_blkcipher.
 406  *
 407  *      In case of error the return value is an error pointer.
 408  */
 409 struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
 410 {
 411         struct crypto_tfm *tfm;
 412         int err;
 413
 414         for (;;) {
 415                 struct crypto_alg *alg;
 416
 417                 alg = crypto_alg_mod_lookup(alg_name, type, mask);
 418                 if (IS_ERR(alg)) {
 419                         err = PTR_ERR(alg);
 420                         goto err;
 421                 }
 422
 423                 tfm = __crypto_alloc_tfm(alg, type, mask);
 424                 if (!IS_ERR(tfm))
 425                         return tfm;
 426
 427                 crypto_mod_put(alg);
 428                 err = PTR_ERR(tfm);
 429
 430 err:
 431                 if (err != -EAGAIN)
 432                         break;
 433                 if (signal_pending(current)) {
 434                         err = -EINTR;
 435                         break;
 436                 }
 437         }
 438
 439         return ERR_PTR(err);
 440 }
 441 EXPORT_SYMBOL_GPL(crypto_alloc_base);
 442
 443 void *crypto_create_tfm(struct crypto_alg *alg,
 444                         const struct crypto_type *frontend)
 445 {
 446         char *mem;
 447         struct crypto_tfm *tfm = NULL;
 448         unsigned int tfmsize;
 449         unsigned int total;
 450         int err = -ENOMEM;
 451
 452         tfmsize = frontend->tfmsize;
 453         total = tfmsize + sizeof(*tfm) + frontend->extsize(alg);
 454
 455         mem = kzalloc(total, GFP_KERNEL);
 456         if (mem == NULL)
 457                 goto out_err;
 458
 459         tfm = (struct crypto_tfm *)(mem + tfmsize);
 460         tfm->__crt_alg = alg;
 461
 462         err = frontend->init_tfm(tfm);
 463         if (err)
 464                 goto out_free_tfm;
 465
 466         if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
 467                 goto cra_init_failed;
 468
 469         goto out;
 470
 471 cra_init_failed:
 472         crypto_exit_ops(tfm);
 473 out_free_tfm:
 474         if (err == -EAGAIN)
 475                 crypto_shoot_alg(alg);
 476         kfree(mem);
 477 out_err:
 478         mem = ERR_PTR(err);
 479 out:
 480         return mem;
 481 }
 482 EXPORT_SYMBOL_GPL(crypto_create_tfm);
 483
 484 struct crypto_alg *crypto_find_alg(const char *alg_name,
 485                                    const struct crypto_type *frontend,
 486                                    u32 type, u32 mask)
 487 {
 488         struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask) =
 489                 crypto_alg_mod_lookup;
 490
 491         if (frontend) {
 492                 type &= frontend->maskclear;
 493                 mask &= frontend->maskclear;
 494                 type |= frontend->type;
 495                 mask |= frontend->maskset;
 496
 497                 if (frontend->lookup)
 498                         lookup = frontend->lookup;
 499         }
 500
 501         return lookup(alg_name, type, mask);
 502 }
 503 EXPORT_SYMBOL_GPL(crypto_find_alg);
 504
 505 /*
 506  *      crypto_alloc_tfm - Locate algorithm and allocate transform
 507  *      @alg_name: Name of algorithm
 508  *      @frontend: Frontend algorithm type
 509  *      @type: Type of algorithm
 510  *      @mask: Mask for type comparison
 511  *
 512  *      crypto_alloc_tfm() will first attempt to locate an already loaded
 513  *      algorithm.  If that fails and the kernel supports dynamically loadable
 514  *      modules, it will then attempt to load a module of the same name or
 515  *      alias.  If that fails it will send a query to any loaded crypto manager
 516  *      to construct an algorithm on the fly.  A refcount is grabbed on the
 517  *      algorithm which is then associated with the new transform.
 518  *
 519  *      The returned transform is of a non-determinate type.  Most people
 520  *      should use one of the more specific allocation functions such as
 521  *      crypto_alloc_blkcipher.
 522  *
 523  *      In case of error the return value is an error pointer.
 524  */
 525 void *crypto_alloc_tfm(const char *alg_name,
 526                        const struct crypto_type *frontend, u32 type, u32 mask)
 527 {
 528         void *tfm;
 529         int err;
 530
 531         for (;;) {
 532                 struct crypto_alg *alg;
 533
 534                 alg = crypto_find_alg(alg_name, frontend, type, mask);
 535                 if (IS_ERR(alg)) {
 536                         err = PTR_ERR(alg);
 537                         goto err;
 538                 }
 539
 540                 tfm = crypto_create_tfm(alg, frontend);
 541                 if (!IS_ERR(tfm))
 542                         return tfm;
 543
 544                 crypto_mod_put(alg);
 545                 err = PTR_ERR(tfm);
 546
 547 err:
 548                 if (err != -EAGAIN)
 549                         break;
 550                 if (signal_pending(current)) {
 551                         err = -EINTR;
 552                         break;
 553                 }
 554         }
 555
 556         return ERR_PTR(err);
 557 }
 558 EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
 559
 560 /*
 561  *      crypto_destroy_tfm - Free crypto transform
 562  *      @mem: Start of tfm slab
 563  *      @tfm: Transform to free
 564  *
 565  *      This function frees up the transform and any associated resources,
 566  *      then drops the refcount on the associated algorithm.
 567  */
 568 void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
 569 {
 570         struct crypto_alg *alg;
 571
 572         if (unlikely(!mem))
 573                 return;
 574
 575         alg = tfm->__crt_alg;
 576
 577         if (!tfm->exit && alg->cra_exit)
 578                 alg->cra_exit(tfm);
 579         crypto_exit_ops(tfm);
 580         crypto_mod_put(alg);
 581         kzfree(mem);
 582 }
 583 EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
 584
 585 int crypto_has_alg(const char *name, u32 type, u32 mask)
 586 {
 587         int ret = 0;
 588         struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
 589
 590         if (!IS_ERR(alg)) {
 591                 crypto_mod_put(alg);
 592                 ret = 1;
 593         }
 594
 595         return ret;
 596 }
 597 EXPORT_SYMBOL_GPL(crypto_has_alg);
 598
 599 MODULE_DESCRIPTION("Cryptographic core API");
 600 MODULE_LICENSE("GPL");